Hello Tonia,
I’m working at PI, the manufacturer of the PI E-517.
We have developed a driver for EPICS that supports our controllers.
Maybe this does not show the problem you have, or you can look at the source code, how we implemented it.
The sources can be found on sourceforge:
http://sourceforge.net/projects/piasyn/
(I had some trouble with the mercurial repository and our firewall.
Please download the tgz archive.)
The driver will probably be part of the next motor release.
Best regards
Steffen Rau